Vehicle suspension

ABSTRACT

An H-frame vehicle suspension, having pivoted arms joined by a transverse member, has its arms (10) pivoted within enclosures (16) connected to or incorporated in the vehicle structure, such enclosures also containing springs (19) operating on the arms. The springs are preferably of fiber reinforced plastics material.

This invention relates to a suspension for a vehicle. Particularly, andin the embodiment hereafter described, the suspension is suitable forthe rear wheels of a passenger car, but it will be appreciated theinvention is more widely applicable to vehicles generally.

Motor vehicle suspensions of the so-called H-frame type are well known,utilizing a member of generally H-shape in plan view comprising twospaced arms, one at each side of the vehicle, and a transverse elementconnecting the arms. Each of the arms is pivotally connected to thevehicle structure at its one end and carries a wheel assembly at itsother end. The transverse element acts as a bracing member to assistmaintenance of the desired relative alignment of the two wheels, andalso acts to resist roll of the vehicle by resilient twisting when thewheels attempt to undergo different vertical displacements relative tothe vehicle. In such suspensions as proposed hitherto, springing isusually provided by coil springs, operative between the arms and thevehicle structure at positions remote from the arm pivots, although ithas also been proposed that leaf springs may be used. Such anarrangement has a disadvantage in that the structure of the vehicle hasto be designed to provide space to accommodate the springs, and to takethe loads which arise in use at the points where the springs areconnected to the vehicle structure. Such suspensions are, however,widely used, particularly for the rear wheels of front-wheel-driveautomobiles.

It is the object of the present invention to provide an improvedsuspension of the H-frame type, in which these disadvantages areovercome or reduced. Further advantages of the suspension according tothe invention will be pointed out hereafter.

The present invention provides a suspension for a vehicle, comprising amember of generally H-shape in plan view, having two spaced arms eachprovided at or adjacent at its one end with means to carry a wheelassembly, and a transverse element extending between said arms, the armshaving portions at their other ends which are pivotally connected to thevehicle, wherein each of said pivotal connections is established in anenclosure means connected to or forming part of the structure of thevehicle, each such enclosure means also containing a leaf springengaging the arm to provide springing between the respective wheel andthe vehicle structure.

In a suspension according to the invention, the vehicle structure has tobe designed to receive or constitute the enclosure means for each arm ofthe H-shape member, but no additional provision is necessary for springsremote from the pivots of the arms. It is contemplated that asimplification of the vehicle structure and weight and cost savings mayresult. In a preferred embodiment of the suspension, the enclosure meansform parts of sill structures of the vehicle. In a vehicle such as apassenger car of unitary body construction, the sills of the bodystructure are strong and rigid, and hence suitable for being providedwith pivots for the arms and for engagement with the leaf springs.

Preferably each said leaf spring extends at its one end into theassociated arm, is pivotally supported between its ends relative to thearm, and reacts, at or adjacent its other end, against a reaction memberwithin said enclosure means. Preferably each leaf spring is ofcomposite, fibre-reinforced plastics, material, and a pivotal support ofeach such spring is in alignment with the pivotal connection of therespective arm. Use of leaf springs of fibre reinforced plasticsmaterial enables weight to be reduced.

Dampers of telescopic type may be utilised with the suspension accordingto the invention, such dampers being disposed generally vertically andconnected between the arms, adjacent the wheels held thereby, andadjoining parts of the vehicle structure. Such dampers do not occupy asmuch space as would be required for similarly disposed coil spring, andhence their presence does not greatly detract from the advantages of theinvention Further, such dampers may be of the known type providing aself-levelling action.

The invention will now be described by way of example with reference tothe accompanying drawings, of which:

FIG. 1 is a plan view of a suspension according to the invention;

FIG. 2 is an elevation of the suspension of FIG. 1.

The illustrated suspension comprises a member which is of generallyH-shape in plan view, having two spaced arms 10 and an element 11extending transversely of the vehicle between the arms. The longitudinalcentre line of the vehicle is indicated at 12, and the parts of thesuspension are mirror image identical to one another on opposite sidesof the centre line 12. Each arm 10 is fabricated from sheet metal partswelded together, and comprises a portion 13 extending rearwardly andoutwardly from the end of the transverse element 11, supporting a stubaxle 14 for carrying a wheel indicated in outline at 15. Forwardly oftransverse element 11, each arm comprises a box section portion 16,which extends into an enclosure 17 which as illustrated in FIG. 2 of thedrawings, may be connected to or form part of a sill structure 18 of amotor vehicle.

The transverse element 11 is of tubular form, and is rigidly secured tothe arms 11 so as to be both bent and torsionally deflected when thewheels attempt to undergo different vertical movements from one anotherrelative to the vehicle. In addition to assisting maintenance of desiredwheel alignment, element 11 thus resists roll of the vehicle.

The portions 16 of arms 10 are each provided with aligned trunnions 19which are carried in suitable bushes 20 in the respective enclosure 17,so that the arms are pivotally mounted relative to the vehiclestructure.

A leaf spring 21 is provided within each enclosure 17, extending intothe interior of the associated arm portion 16. Spring 21 is ofcomposite, fibre-reinforced plastics, material, and is of generallyrectangular cross sectional shape and may taper in its thickness. Therearmost end of spring 21 bears down on an abutment surface 22 providedin an end part of tubular transverse member 11 within the arm, andbetween its ends, in alignment with trunions 19, a part cylindricalbearing element 23 on the spring lies within a correspondingly partcylindrical formation 24 provided in the upper wall of the arm portion16. The bearing element 23 on the spring may be of a plastics material,e.g. an appropriate grade of nylon, and may be formed in situ on thespring by an injection moulding, possibly a reaction injection moulding,process. At its forward end, spring 21 bears against a reaction surface25 provided within enclosure 17.

It will be appreciated that springs 21 are subject to bending deflectionwhen the wheels move vertically relative to the vehicle structure.Reaction surfaces 25 within the enclosures 17 may be so shaped that arising spring rate is obtained, by arranging that as each springdeflects the position of its effective point of abutment with itsrespective reaction surface is proved lengthwise of the spring towardsthe associated arm.

Damping of the sprung wheel movement may be obtained by telescopicdamper units 26 as shown in FIG. 2, disposing in generally uprightorientations and connected between brackets 27, at the ends of armportions 13, and suitable attachment points on the vehicle structure.Such damper units may be of the known type which provides aself-levelling action.

The invention thus provides a suspension which is readily incorporatedin a vehicle and occupies little space as compared with generally knownsuspensions. Particularly the majority of the space between the wheelsis unoccupied by suspension parts, since the dampers 26 do not requirelarge spaces for their accommodation. The springs are disposed in partsof the vehicle which, as explained above, are intrinsically strong andwell suited to their accommodation, enabling a simplification in vehiclestructure.

We claim:
 1. A suspension for a vehicle structure, comprising:a memberof generally H-shape in plan view, having two spaced arms and an elementextending transversely of the vehicle between said arms; means atcorresponding ends of said arms for carrying wheel assemblies; pivotmeans at the other ends of said arms, for establishing pivotalconnections thereof to the vehicle structure; respective enclosure meanswherein each of said pivotal connections is established, each saidenclosure means being connected to the vehicle structure; a respectiveleaf spring of fibre-reinforced plastics material disposed in each saidenclosure means; a pivotal support for each said spring, said pivotalsupport being in alignment with the pivotal axis of the respective armand supporting the spring relative to the arm; an abutment surface inthe respective arm, abutted by an end of the spring spaced from saidpivotal support thereof; and a reaction surface within the respectiveenclosure means, engaged by an opposite end of the spring spaced fromsaid pivotal support thereof, whereby the spring resiliently resistspivotal movement of the respective arm.
 2. A suspension according toclaim 1 wherein said enclosure means form parts of sill structures (18)of the vehicle.
 3. A suspension according to claim 1 wherein saidpivotal support is provided by a part-cylindrical formation (23) on thespring occupying a part-cylindrical formation (24) in the arm.